WATSON, IL - Illinois state child-welfare officials have taken a southern Illinois boy into protective custody after authorities say his 7-year-old sister was stabbed to death by a live-in uncle.

Illinois Department of Children & Family Services spokesman Dave Clarkin says that before Willow Long was killed last weekend, the agency had no involvement with the Effingham County family. The boy is 3.

Twenty-two-year-old Justin DeRyke was charged Wednesday with first-degree murder. Prosecutors say he told investigators he killed his niece to end her suffering after she accidentally fell onto a brush pile and pierced her neck with a stick near the family's Watson home.

DeRyke is jailed on $5 million bond and hiring an attorney. He's set to appear again in court next Thursday.